The present invention relates to an avoidance system, and more particularly to an avoidance system which includes a geographical database to avoid interference with known sensitive ground based instruments and thereby accommodating particular regulations or other restrictions.
Various systems have been developed to minimize the likelihood that a rotary wing aircraft will contact obstacles, such as telephone lines, etc., while flying at low levels. Current techniques include active electronic systems such as microwave and millimeter wave radar systems, passive systems which detect the magnetic flux from a live transmission line, and mechanical systems which cut the wires upon contact.
Disadvantageously, these ground obstacles alert systems may interfere with sensitive ground based instruments such as radio-telescopes. Ground obstacles alert systems are thereby subject to regulations such as those propagated by various government agencies such as the FCC. Specialized emitters which operate on particular frequencies which avoid interference are thereby utilized with aircraft ground obstacle alert systems. Although effective, ground obstacles alert systems with specialized emitters are relatively expensive which may limit common introduction of these systems into aircraft. Additionally, aircraft often are required to avoid other types of areas such as, but not exhaustively including, sports arenas, sensitive areas near power plants, hospitals, sensitive Government facilities, retirement developments, etcetera whether or not these facilities emit radio frequencies.
Accordingly, it is desirable to provide an inexpensive avoidance system which avoids interference with sensitive ground-based instruments and geographic areas.